Add a pre-commit setup

Author: brandonwillard

.pre-commit-config.yaml

@@ -0,0 +1,35 @@
+repos:
+  - repo: https://github.com/psf/black
+    rev: 20.8b1
+    hooks:
+      - id: black
+        language_version: python3
+        exclude: |
+            (?x)^(
+                versioneer\.py|
+                cons/_version\.py|
+                doc/.*|
+                bin/.*
+            )$
+  - repo: https://gitlab.com/pycqa/flake8
+    rev: 3.8.4
+    hooks:
+      - id: flake8
+        exclude: |
+            (?x)^(
+                versioneer\.py|
+                cons/_version\.py|
+                doc/.*|
+                bin/.*
+            )$
+  - repo: https://github.com/pycqa/isort
+    rev: 5.7.0
+    hooks:
+      - id: isort
+        exclude: |
+            (?x)^(
+                versioneer\.py|
+                cons/_version\.py|
+                doc/.*|
+                bin/.*
+            )$

README.md

@@ -1,12 +1,10 @@
 [![Build Status](https://travis-ci.org/pythological/python-cons.svg?branch=master)](https://travis-ci.org/pythological/python-cons) [![Coverage Status](https://coveralls.io/repos/github/pythological/python-cons/badge.svg?branch=master)](https://coveralls.io/github/pythological/python-cons?branch=master) [![PyPI](https://img.shields.io/pypi/v/cons)](https://pypi.org/project/cons/)
 
-Python `cons`
-==================
+# Python `cons`
 
 An implementation of [`cons`][cons] in Python.
 
-Usage and Design
-======================
+## Usage and Design
 
 The `cons` package attempts to emulate the semantics of Lisp/Scheme's `cons` as closely as possible while incorporating all the built-in Python sequence types:
 ```python
@@ -52,8 +50,7 @@ ConsPair('a' 'a string')
 This setting can be overridden and other types can be similarly excluded from consideration by registering classes with the `abc`-based classes `MaybeCons` and `NonCons`.
 
 
-Features
-===========
+## Features
 
 * Built-in support for the standard Python ordered sequence types: i.e. `list`, `tuple`, `Iterator`, `OrderedDict`.
 ```python
@@ -77,13 +74,29 @@ OrderedDict([('a', 1)])
 
 ```
 
-Installation
-================
+## Installation
 
 ```python
 pip install cons
 ```
 
+### Development
+
+First obtain the project source:
+```bash
+git clone git@github.com:pythological/python-cons.git
+```
+
+Create a virtual environment and install the development dependencies:
+```bash
+$ pip install -r requirements.txt
+```
+
+Set up `pre-commit` hooks:
+
+```bash
+$ pre-commit install --install-hooks
+```
 
 [cons]: https://en.wikipedia.org/wiki/Cons
 [un]: https://github.com/pythological/unification

cons/__init__.py

@@ -1,8 +1,6 @@
-from .core import cons, car, cdr  # noqa: F401
-
 from . import unify  # noqa: F401
-
 from ._version import get_versions
+from .core import car, cdr, cons  # noqa: F401
 
 __version__ = get_versions()["version"]
 del get_versions

cons/core.py

@@ -1,9 +1,9 @@
-from abc import ABCMeta, ABC, abstractmethod
+from abc import ABC, ABCMeta, abstractmethod
+from collections import OrderedDict, UserString
+from collections.abc import ByteString, ItemsView, Iterator, Mapping, Sequence
 from functools import reduce
-from operator import length_hint
 from itertools import chain, islice
-from collections import OrderedDict, UserString
-from collections.abc import Iterator, Sequence, ItemsView, ByteString, Mapping
+from operator import length_hint
 
 from multipledispatch import dispatch
 
@@ -17,10 +17,7 @@ class ConsError(ValueError):
 
 class ConsType(ABCMeta):
     def __instancecheck__(self, o):
-        return (
-            issubclass(type(o), (ConsPair, MaybeCons))
-            and length_hint(o, 0) > 0
-        )
+        return issubclass(type(o), (ConsPair, MaybeCons)) and length_hint(o, 0) > 0
 
 
 class ConsNullType(ABCMeta):
@@ -86,9 +83,9 @@ def __new__(cls, *parts):
         elif len(parts) == 2:
             car_part, cdr_part = parts
 
-            if isinstance(
-                cdr_part, (ConsNull, ConsPair, Iterator)
-            ) and not issubclass(type(cdr_part), ConsPair):
+            if isinstance(cdr_part, (ConsNull, ConsPair, Iterator)) and not issubclass(
+                type(cdr_part), ConsPair
+            ):
                 res = cls.cons_merge(car_part, cdr_part)
             else:
                 instance = super(ConsPair, cls).__new__(cls)
@@ -146,9 +143,7 @@ def __str__(self):
 class MaybeConsType(ABCMeta):
     def __subclasscheck__(self, o):
 
-        if issubclass(o, tuple(_cdr.funcs.keys())) and not issubclass(
-            o, NonCons
-        ):
+        if issubclass(o, tuple(_cdr.funcs.keys())) and not issubclass(o, NonCons):
             return True
 
         return False
@@ -165,7 +160,7 @@ class MaybeCons(metaclass=MaybeConsType):
     The potential cons types are drawn from the implemented `cdr` dispatch
     functions.
 
-    """
+    """  # noqa: E501
 
     @abstractmethod
     def __init__(self):

cons/unify.py

@@ -1,13 +1,9 @@
-from itertools import tee
 from collections.abc import Iterator, Mapping
+from itertools import tee
 
-from unification.core import (
-    _unify,
-    _reify,
-    construction_sentinel,
-)
+from unification.core import _reify, _unify, construction_sentinel
 
-from .core import car, cdr, ConsPair, cons, MaybeCons, ConsError
+from .core import ConsError, ConsPair, MaybeCons, car, cdr, cons
 
 
 def _unify_Cons(lcons, rcons, s):

pyproject.toml

@@ -1,5 +1,6 @@
 -e ./
 coveralls
+isort
 pydocstyle>=3.0.0
 pytest>=5.0.0
 pytest-cov>=2.6.1
@@ -8,3 +9,5 @@ pylint>=2.3.1
 black>=19.3b0; platform.python_implementation!='PyPy'
 diff-cover
 versioneer
+coverage>=5.1
+pre-commit

requirements.txt

@@ -24,3 +24,23 @@ exclude_lines =
     pragma: no cover
 
     raise NotImplementedError
+
+[isort]
+multi_line_output = 3
+include_trailing_comma = True
+force_grid_wrap = 0
+use_parentheses = True
+ensure_newline_before_comments = True
+line_length = 88
+
+[flake8]
+max-line-length = 88
+extend-ignore = E203, W503
+per-file-ignores =
+    **/__init__.py:F401,E402,F403
+
+[pylint]
+max-line-length = 88
+
+[pylint.messages_control]
+disable = C0330, C0326

setup.cfg

@@ -1,9 +1,9 @@
 #!/usr/bin/env python
-import versioneer
-
 from os.path import exists
+
 from setuptools import find_packages, setup
 
+import versioneer
 
 setup(
     name="cons",
@@ -26,7 +26,7 @@
         "Intended Audience :: Science/Research",
         "Intended Audience :: Developers",
         "License :: DFSG approved",
-        "License :: OSI Approved :: GNU Lesser General Public License v3 or later (LGPLv3+)",
+        "License :: OSI Approved :: GNU Lesser General Public License v3 or later (LGPLv3+)",  # noqa: E501
         "Operating System :: OS Independent",
         "Programming Language :: Python",
         "Programming Language :: Python :: 3",

setup.py

@@ -1,20 +1,12 @@
-import pytest
-
-from itertools import chain, cycle
 from collections import OrderedDict, UserList
 from collections.abc import Iterator
+from itertools import chain, cycle
 
-from unification import unify, reify, var
+import pytest
+from unification import reify, unify, var
 
-from cons import cons, car, cdr
-from cons.core import (
-    ConsPair,
-    MaybeCons,
-    ConsNull,
-    ConsError,
-    NonCons,
-    ProperSequence,
-)
+from cons import car, cdr, cons
+from cons.core import ConsError, ConsNull, ConsPair, MaybeCons, NonCons, ProperSequence
 
 
 def test_noncons_type():
@@ -111,9 +103,7 @@ def test_cons_join():
     assert cons("a", ["b", "c"]) == ["a", "b", "c"]
     assert cons("a", ("b", "c")) == ("a", "b", "c")
     assert type(cons(("a", 1), {"b": 2})) == ConsPair
-    assert cons(("a", 1), OrderedDict({"b": 2})) == OrderedDict(
-        [("a", 1), ("b", 2)]
-    )
+    assert cons(("a", 1), OrderedDict({"b": 2})) == OrderedDict([("a", 1), ("b", 2)])
 
     assert cons(["a", "b"], "c") == ConsPair(["a", "b"], "c")